Minshull, Roger
Hutchinson University Library, 1971
Buku Teks
Blunt, Alison
Prentice-Hall, 2000
Buku Teks
N. Daldjoeni, author
Alumni, 1998
Buku Teks
Wooldridge, S. W.
Hutchinson University Library,, 1970
Buku Teks
Soja, Edward W.
New York , 1989
Buku Teks